P0306 - Cylinder 6 Misfire Detected
P0306 is a generic powertrain diagnostic trouble code indicating Cylinder 6 Misfire Detected. It relates to the Ignition System / Misfire system.
DTC Breakdown (SAE J2012)
| System | Powertrain (P) |
| Type | Generic |
| Subsystem | Ignition System / Misfire |
| Fault Index | 06 |
| Standard | SAE J2012 / ISO 15031-6 |
What does diagnostic code P0306 mean?
The onboard diagnostics have detected that cylinder number 6 is misfiring and failing to complete the combustion cycle.
Severity Level & Driveability Details
Severity: High
Raw fuel in the exhaust will overheat and melt the catalytic converter. A flashing check engine light indicates active misfires in Cylinder 6.
Common Symptoms of P0306
- Continually flashing check engine light during active combustion failure.
- Rough engine idle and shaking.
- Severe power loss.
- Exhaust odor of unburned fuel.
Typical Causes for P0306
- Faulty ignition coil on cylinder 6.
- Worn or fouled spark plug on cylinder 6.
- Bad cylinder 6 fuel injector.
- Low cylinder 6 compression (valves or head gasket).
Diagnostic and Troubleshooting Steps
Move the cylinder 6 coil to another cylinder. If the misfire follows the coil, replace it. Otherwise, check the plug, fuel injector, and run a compression test on cylinder 6.
Typical Repairs and Fixes
- Replacing the ignition coil or spark plug on cylinder 6.
- Replacing the cylinder 6 fuel injector.
- Repairing mechanical cylinder damage.
Sensor Location & Parts Involved
The ignition coil and spark plug for cylinder 6 are located on top of the cylinder head on the engine block.
Clearing Code & Recurrence
Resolve the underlying ignition or fuel fault in cylinder 6, then reset the codes using an OBD2 scanner.
Emissions & Smog Inspection Impact
Misfiring in cylinder 6 releases unburned hydrocarbons into the exhaust stream, potentially damaging the catalytic converter and raising emissions.
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Related Diagnostic Codes
Sources & References
This diagnostic guide is compiled and verified against the following authority sources:
- NHTSA Recall Database
- EPA OBD II Regulations
Frequently Asked Questions about P0306
What does the cylinder 6 misfire code P0306 mean?
The engine control module logged P0306 after detecting a combustion misfire in cylinder 6. This indicates that the fuel-air mixture is failing to ignite properly inside the cylinder 6 chamber.
Is it safe to drive with the cylinder 6 misfire code P0306 active?
No, driving with active misfires in cylinder 6 can ruin the catalytic converter.
How much does it cost to repair a cylinder 6 misfire code P0306 fault?
Replacing an ignition coil or spark plug for cylinder 6 typically costs $100-$300. Replacing the fuel injector for cylinder 6 costs $200-$450.
What are the common causes of the cylinder 6 misfire code P0306?
Trigger conditions for the cylinder 6 misfire code P0306 include: A worn or fouled spark plug in cylinder 6., Failed ignition coil or damaged spark plug wire for cylinder 6., Faulty fuel injector or poor fuel atomization in cylinder 6..
Can I clear the check engine light for cylinder 6 misfire code P0306?
Resolve the underlying ignition or fuel fault in cylinder 6, then reset the codes using an OBD2 scanner.
Will the cylinder 6 misfire code P0306 cause an inspection failure?
Misfiring in cylinder 6 releases unburned hydrocarbons into the exhaust stream, potentially damaging the catalytic converter and raising emissions.